ISO and Vista?

[Teny]

so my friend got some movie DVDs, and i asked if i can make a back up onto my computer so i can watch it whenever i want when i am at home, and he said okay.
I am using Vista and Poweriso, and like every time i mount the DVD, it usually doesnt get the menu to work right, for example, i cant slick on the settings or play movie, and sometimes it just takes a whole lot of ram, like 98% of it and makes my computer slow.
so long story short, whats the best mount program that is able to watch DVDs and wont slow down my computer?
Thanks

 

[CrossCech]

I use Alchohol 120% Virtual CD/DVD Drive to mount. Doesn't hog cpu when I mount an ISO movie. And I also am pleased with video playback quality from WinDVD 9.